Acid Precipitation: Natural Versus Anthropogenic Components

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Science  16 Nov 1984:
Vol. 226, Issue 4676, pp. 829-831
DOI: 10.1126/science.226.4676.829


The concentrations of H+, SO42-, and NO3- in the precipitation of eastern North America are greater now than they were historically as a result of fossil-fuel combustion. Because of a lack of data prior to 1950, the absolute increases in the concentrations of these three ions are unknown. This problem can be addressed by comparing the composition of precipitation from areas sensitive to acidic deposition with that of precipitation from remote areas. An analysis of precipitation data indicates that many areas of eastern North America receive precipitation with substantially greater H+, SO42-, and NO3- concentrations than remote areas. For example, SO42-, the most ecologically significant indicator of change, is enriched 2 to 16 times in eastern North American precipitation relative to its concentration in remote areas.